Integrated Pest Management: Comb Trapping.

October.

October draws to a close and Halloween approaches: the bees have taken advantage of the plentiful warm autumn days to stock up the store cupboard. Amazingly, Himalayan balsam is still coming in having been flowering since 13th August, but ivy and viburnum are attracting lots of bees now. I’ve given each colony some fondant as an insurance policy though I know they have honey stores to fall back on as winter takes a grip.

Thank you to everyone who donated to the upkeep of the website, and welcome to the new beelistener subscribers who joined to receive free weekly blogs. Hello to readers from Ghana and Luxemburg who tuned in this month bringing the blog to 108 countries.

On Tour.

The sun catches High Bellochantuy farm, Kintyre.

I’ve had some time away after over a year of being at home and it was refreshing to have a change. Firstly, I visited close family in Argyll, on the west coast, and in Midlothian on the east. I swam in the sea at Cleit beach near Muasdale which is my favourite beach. The sea was lovely in October with the gulf stream warming the Atlantic ocean: slightly! Rain was never far away as is the case on the west coast.

The Old and the New.

Garbhalt Cottage

Walking up the glen a mile from Arnicle farm where I grew up, I reached Garbhalt cottage. I was struck by the changes since my last visit only a couple of years ago. The new windfarm reaching up to the sky looms over Arnicle below it at the end of the glen road, and nods over to the long- abandoned Garbhalt dwelling house across the glen. I remember the last inhabitants who left in the late 1960’s or early ’70’s. They were a shepherd and his mother and they had electricity but no car or television. We didn’t have a television either but we did have a car and could drive to Campbeltown 15 miles away for shopping.

In the 1950s and ’60’s, grocery and butcher vans serviced remote farms and communities. There is a tarred 3-mile road leading from the main road to our farm, but the Macleans had to walk down from Garbhalt to our farm to get food supplies from the vans, and the living must have been tough and lonely for them.

Midlothian.

Hawthorn Hedge, Pathhead, Midlothian.

The rich arable land of the east coast, south of Edinburgh, contrasts with the more rugged wetter west coast. I take an early morning walk along field paths. Farmers make these accessable to walkers and it is a joy to walk over them in bright autumn sunlight and notice hedges breaking up the fields of autumn sown oil seed rape. Hawthorn, Crataegus species, not only provides pollen and nectar but also abundant food and shelter for birds and other animals.

Honey bee on ivy, Hedera helix.

I can’t stay away from bees for more than a few days. I try not to talk bees with my relatives but I’m invited to lunch at Newbattle with one of my favourite beekeeping associations and it’s bee talk all afternoon. It’s only a few miles from Pathhead and I arrive too early so I walk round the magnificent grounds of Newbattle Abbey where the association apiary and Bee Academy are situated.

The ivy was being worked by numerous pollinators and the sun shone on a vigorous bee who showered glittering pollen everywhere it went. The pollen looked like fairy dust trapped in sunbeams. I used the photograph as the focus of an impromptu presention to the Junior Beekeeping Club who come to the academy on Friday afternoons. The school children were aged between 12-13 years and I was impressed by their prior knowledge and willingness to engage with me. However, it is not really a surprise because Newbattle Beekeeper’s Association is renouned for it’s positive approach to education and training, and operates as a team utilising the diverse skills of individual members. Look out for a future guest blog from Neil Rutherford who leads the Junior Beekeeping Club.

Integrated Pest Management.

Cage to hold comb with trapped queen.

Some time ago, Megan Denver asked what I was going to with the comb trapping cages that I’d mentioned briefly. I didn’t use them this year because all my colonies had brood breaks during swarm season and I was happy that varroa levels were very low. I’ll answer the question now though I’m not speaking from personal experience having never tried it before. So, if anyone out there has experience with comb trapping please share it with us.

Integrated pest management (IPM) is both a science-based and a common sense-based approach to pest and disease management. It is about reducing populations of disease vectors and pests in a systematic way that employs various techniques to reduce those risks as well as reducing the overuse, or innappropriate use, of hazardous pest control chemicals and products which are not good for the environment.

IPM is used widely in all forms of agriculture, farming and in human public health. In simple terms the principles are: don’t attract pests in the first place, keep them out and get rid of them when they arrive. But of course it is a lot more complicated in beekeeping and we can never completely get rid of varroa so we don’t try: however, we do aim to keep them below levels that damage a colony.

Science to the Rescue.

The National bee unit in the UK has modelled varroa and calculated levels at which colonies are under most risk from varroa damage throughout the year. Beekeepers have access to the varroa calculator which is a marvellous tool and we can see at a glance whether we need to treat or not: https://nationalbeeunit.com/public/BeeDiseases/varroaCalculator.cfm

In the past, chemical treatments ( acaricides/miticides) for varroa were liberally thrown at the problem by nearly every beekeeper. We now know that this leads to resistance eventually with every new chemical brought to market, and it produces a stronger and more resilient varroa mite that requires a stronger and more powerful chemical to kill it.

Know the Enemy.

“If you know the enemy and know yourself, you need not fear the result of a hundred battles. If you know yourself but not the enemy, for every victory gained you will also suffer a defeat. If you know neither the enemy or yourself, you will succumb in every battle.” Sun Tzu, The Art of War, 5th Century BC.

If we are to have any success with IPM we need to understand fully the life cycle of the varroa mite because we need to hit them when they are most vulnerable using a range of diffferent methods which might include chemicals, or prevention using what we call biotechnical methods.

Chemicals kill varroa outright, but biotechnical methods disrupt the varroa life cycle and work by delaying the build up of populations within a colony which reduces the need for using a chemical.

Biotechnical Methods.

Biotechnical methods include: using open mesh floors, removing drone brood and giving the colony a brood break. I’m not including shaking icing sugar over the frames because I’ve tried it and I believe that it increases the risks of robbing, and attracting wasps, more than doing anything useful towards reducing varroa by causing the mite to lose its grip on the bee body. Varroa are most likely to be hidden away between the plates on the honey bee exoskeleton so dusting with icing sugar is a waste of time and sugar.

Brood Breaks.

We know from work by Professor Tom Seeley and colleagues that the Arnot Forest bees living in the wild, unlike managed and maniplated colonies, have smaller colonies and swarm freely. They have evolved to resist varroa living in that environment without beekeeping management and interference. Brood breaks interrupt the varroa life cycle and this is when varroa will be found traveling on the bee in the phoretic stage and when they are vulnerable to oxalic acid treatments for example.

Artificial and shook swarms achieve brood breaks also, as does caging the queen alone in a small cage on comb for 25 days. I toyed with the idea of trying the latter and ordered some cages from Italy. After 3 months, I contacted the company to find out why they hadn’t arrived. By this time, I’d learned that this method can often cause the colony to supersede the queen once she is released from the cage so I was quite pleased to discover that my order had been cancelled due to my AMEX card not being accepted. Instead, Fred from Dundee made me the splendid trapping cages photographed above.

Comb Trapping.

Comb trapping was first used by V. Maul in Germany in the 1980’s when varroa first arrived in Europe and it works on the principle that varroa must enter the brood cell shortly before capping so that they can settle in to reproduce. However, for this to work there must be no other brood cells available for varroa to enter. This is achieved over a 36-day period using 3 combs. The method requires 5 colony inspections so may not be practical for every beekeeper but I shall give it a go next season.

The trapping frames are expensive but many beekeepers are resourceful and skilled enough to make their own more cheaply than can be obtained from bee supply companies.

Because all 3 brood frames will be destroyed, I shall use old ones that need to be changed anyway. If I do it correctly I might find over 90% efficiency in varroa removal. I could also treat with oxalic acid at the end of the comb trapping to increase efficiency further.

When?

It is best to use this method before the main nectar flow and in good time before the colony produces its winter bees because this method does cause a decline in adult bee populations. However, the good thing about it is that there are not so many brood mouths to feed so more workers are foraging and converting nectar into honey for storage. In most parts of the UK the main flow is in July/August so the best time to trap is mid-June so that the queen can get back to full laying capacity by the end of July.

Timing is Key.

Because worker cells are sealed on day 9, the brood frames must be added to the cage every 9 days which demands beekeeper discipline and organisation.

On day 0, I will find the queen and place her on my marked frame (number 1) and place her in the cage surrounded by queen excluder to keep her in but the workers coming and going freely. Because the cage is wider than the other brood frames, I shall need to remove another brood frame to accommodate it in the middle of the brood nest.

Day 9: I will remove frame 1 from the cage and place it in the brood nest. It contains both eggs and larvae just before the cell sealing stage. Frame 2 will be placed in the cage with the queen. I will inspect the colony and keep a look out for any supersedure queen cells, due to the queen being confined, and destroy those.

Day 18: All the brood on frame 1 will be sealed with the mites inside so I shall remove and destroy this comb by firstly freezing it. Frame 2 now contains eggs and larvae ready to be sealed, so this comb is removed from the cage and placed in the brood nest for 9 days while frame 3 is placed with the queen in the cage. Because there are no other unsealed cells in the nest now, the varroa mites have only one option for reproduction and this is in frame 2.

Day 27: I will remove frame 2 and destroy it, and also remove frame 3 from the cage thereby releasing the queen back into the colony. Frame 3 is the only place for varroa to reproduce now so it is left for a further 9 days till all the cells are sealed.

Day 36: The end of the procedure. When frame 3 is destroyed most of the mites within the colony will have been removed. There should be eggs and unsealed brood on the other frames now, but no sealed brood harbouring mites. I shall do a sugar roll test after this to check the levels of varroa present in the colony and test the efficacy of this method. I might use oxalic acid depending on the results. It is worth remembering that in the UK we are legally required to remove honey supers when treating colonies with oxalic acid. This year (2021) in the US it became legal to use oxalic acid with honey supers in place. Clearly oxalic acid doesn’t present risk to human health if used correctly so hopefully our country will follow the US lead on this soon and change our laws.

Steve Riley’s Advice.

Steve has experience of queen frame trapping (QFT) and followed up this blog post with advice on simplifying the method described above:

“it’s far easier to leave the trapped frame in until all the cells are sealed, rather than taking the frame out and putting it in the colony and then taking it out later.  Less faff opening the hive, less mucking around with the queen and you can have a 2 week summer holiday.
We also found 2 rounds of changing the trapped comb was sufficient, as long as the second comb picked up the emerging mites from laying the day before the queen went into the QFT.  In effect, just opening the hive twice.” 

The Process of IPM.

There are 5 main stages in the process of IPM regardless of the techniques used.

  • Inspection and monitoring. Identify disease or pest.
  • Establish the threshold level above which population levels cause harm.
  • Implement one or more control/management strategies that reduces pest access to life, food, shelter and reproduction.
  • Evaluation: has the treatment been effective?
  • What next? This is a very important part of the ongoing management planning process.

Disease.

This blog focused on varroa but think of IPM when contemplating any disease of the honey bee. We use apiary hygiene as part of IPM in managing foulbrood and other infections. Regarding viruses, part of our strategy can be using local bee stocks and not importing queens and packages from other countries and areas that have viral infections which we might not currently have.

Useful Resource.

https://www.bbka.org.uk/shop/bbka-news-integrated-pest-management#

8 thoughts on “Integrated Pest Management: Comb Trapping.”

  1. Hi Ann,

    We were introduced to Queen Frame Trapping to reduce varroa by Dr Ralph Buchler at Gormanston Beekeeping Summer school in 2016 (I think). We started the process mid July-ish (in the flow) and finished mid Aug, so that winter bees were laid clean of mites. As a by product, more of the nectar is stored in the supers as there is a peak foraging force, but fewer brood to look after temporarily. Queen Frame Traps (QFT) replace both summer and winter chemical miticides and are very efficient at removing mites. On the Westerham Beekeepers’ site, there are instructions on how to make a QFT for under a tenner and video of one of the techniques. https://westerham.kbka.org.uk/natural-beekeeping/

    Ralph also covered them at the National Honey Show https://www.youtube.com/watch?v=tuJlgzcQWAg&ab_channel=NationalHoneyShow

    The clinch for us was his research showing larger spring colonies versus those that were treated with chemical miticides.

    We have graphs of the mite drop pre and post the QFT if you think your readers would find that useful?

    Thoroughly enjoying my weekly visit to your part of Scotland – thank you Ann!

    Steve
    P.S. Firstly, this is the research from Ralph Buchler’s team in Germany that convinced us that these methods were worth trying. It compared chemical treatment with formic acid (slow release via a nessenheider evaporator), with “Total brood removal” (Varroa shook swarm in mid Aug) and Caging in July & Aug (Queen Frame Trapping)

    The research methodology was to compare the size of the colonies in the following spring, as a % of their larger summer size. This would gauge how they had overwintered and the strength of brood development in the spring. Colonies numbered 140.

    Graph 1

    In the spring, the Treated colonies averaged 39.5% of their summer size. About the same as Total brood removal. The Caging (Queen Frame Trapping) results were far superior. Why? We think 2 reasons;- 1) QFTs are more effective than chemical miticides at removing varroa 2) There is a negative effect of putting mild poisons on colonies to kill mites.

    We trialled both methods in the summers of 2018 and 2019 – no chemical miticides were used. The graphs show daily mite drop and hopefully it is clear to see what happens after employing Queen Frame Trapping (QFT) and Varroa Shook Swarms (VSS). .

    Graph 2

    In the first season, 26 out of 28 colonies over wintered well, (2 queen issues). The mite levels were so low, particularly for QFTs, that we wrote to Dr Ralph Buchler for assurance that this was ok! They are remarkably efficient.

    [Ann – That’s probably all I promised you……but let’s roll forward another season, as we had substituted chemicals for biotechnical methods and were keen to spot varroa resistant traits, especially uncapping/recapping. Just for your interest or to use as you see fit………..]

    Here is what happened when the Hive 1 colony were left to manage their own varroa population.

    Graph 3

    They outperformed human intervention……LEARNING FROM THE BEES!!!!

    Through the 2021 season just gone, this was by far and away the most productive colony.

    The overall project now encompasses 160 colonies across the Surrey / Kent borders, with c15% using these biotechnical methods and the rest, “no beekeeper intervention”

    1. Hello Steve,
      Thank you for coming in with this information and I think that the readers would also find the graph useful. So, yes please to graph. I’m glad that you enjoy your weekly “visits” and hopefully you can visit in person one day. Best wishes, Ann.

  2. Dear Ann,
    Thank you for describing so clearly and precisely the queen-trapping method of Varroa control. There is just one step in the process that I do not understand: destroying the three frames used for trapping the queen (and gathering the mites). Would the method not work just as well if one were to freeze these three frames, rather than destroy them?
    Thanks again, Ann.
    Tom

    1. Dear Tom,
      Thank you for reading the article and commenting. You could freeze the frames then remove the dead brood and varroa and reuse the combs, but the method I describle incorporates good apiary hygiene practice and destroying the frames becomes part of the cycle of comb change that ensures a set of new brood combs over 3 years. You could render down the wax from these combs and make furniture polish. Of course, many beekeepers change all the comb at once in a shook swarm or Bailey comb change which also give a brood break and can be used in IPM.
      Best wishes
      Ann

    1. Good morning, Chris. Drones are much neeeded for mating and maintaining genetic diversity. They are much more costly for a colony to produce since more resources are needed to feed them adequately. They take 24 days to develop from egg to emergence, then another 10 days for fully functioning reproductive system development. This well-tried system of comb trapping is more economical and efficient in terms of reducing varroa and maintaining good numbers of drones in a colony. See Steve Riley’s guest blog on breeding varroa resistant bees for more information. I hope this explanation is useful. Best wishes, Ann.

  3. Seems there is good evidens that this work well. Will try it on one colony this season I think. Would be good to stop using chemicals, and still avoid getting a “Varroa-bomb” by not treating at all. Here in East Sussex several “low-treating” beekeepers in our BKA have experienced big losses because of the exceptionally mild Winter 2021-2022.

    1. Interesting how some beekeepers instantly attribute winter losses to the weather rather than questioning their own management style. They lose them when the winter is mild or when the winter is harsh!!!!

Leave a Reply

This site uses Akismet to reduce spam. Learn how your comment data is processed.